More than 30 years into the AIDS epidemic, men who have sex with men (MSM) continue to engage in unprotected anal intercourse (UAI) in circumstances in which there is risk of HIV transmission. MSM are the only CDC-defined risk group in the US in which new HIV infections have been increasing steadily since the 1990s. Statistics about HIV among male-to-female transgender women (TGW) are often unavailable but it is known that HIV prevalence in this population is high, and the 2011 Institute of Medicine Consensus Report called for much needed research among transgender populations. Alternatives to condom use are needed for individuals who cannot or will not use condoms. Use of a rapid HIV-home test (HT) to screen potential sexual partners could be an important risk-reduction tool for such population. The primary aim of our study is to determine if high-risk MSM and TGW who have access to HT and learn how to use it with potential sexual partners engage in less sexual risk behavior than MSM and TGW who do not use HT. The secondary aim of the study is to determine if ease of access to HT affects its use to reduce occasions of UAI. This 5-year randomized controlled trial will target mainly, but not exclusively, ethnic minority men and TGW who have sex with men, are HIV-uninfected and non-monogamous, never or seldom use condoms, and have a history of serodiscordant UAI. We will recruit and pre-screen approximately 600 participants in two cities with high HIV prevalence: New York, NY, and San Juan, PR. Given the stringent eligibility criteria of the study, we expect that only 300 participans will be eligible to enroll in the trial after screening at Visit 1. At Visit 2, they will be randomzed in equal numbers to one of two groups: Group A participants will receive an HT intervention orientating them to effective ways of using HT to screen sexual partners and will be supplied with HT kits to use with sexual partners over 6 months; Group B participants will receive neither the HT intervention nor supply of kits, and we will monitor whether they avail themselves of HT kits through purchase or other means. Both groups will receive risk-reduction counseling. All participants' behavior will be monitored for 6 months through daily brief SMS reports. At Visit 3 (6-month evaluation), we will test our primary hypothesis; also, we will discontinue the provision of HT to Group A. Group A will be monitored for three additional months. At Visit 4 (9-month evaluation), we will test our secondary hypothesis. Demonstrating that use of HT is an effective risk-reduction tool can have a high, transformative impact in the HIV prevention field. Additionally, demonstrating the crucial nature of easy access to HT to realizing the potential of HT as a risk-reduction tool may spur action to make HT more accessible to populations most likely to benefit from its use. It will give evidence that use of a biotechnology that is already available and less costly than others (e.g., PrEP) can potentially result in fewer new infections and reduce public health expenditures.